Devices and systems have been implemented for manufacturing three-dimensional product by selectively fusing powder layers on a work table residing in a powder bed. For example, U.S. Pat. No. 7,537,722, which is incorporated herein by reference, discloses a device composed of a powder bed facilitating a work table, a powder dispenser along with a powder raking system to disperse a thin layer of powder on the work table, a vacuum pump to maintain vacuum that may avoid powder contamination, an energy beam created by a ray gun for directing power to the powder bed for powder fusion, elements to control the energy beam directed to the work table, and a controlling computer that stores the information of cross sections of a desired three-dimensional object.
The controlled energy beam selectively melts the thin layer of powder on top of the work table in accordance to the cross-section of a three-dimensional part. The raking system spreads a new layer of powder on top of the powder bed and fusion of the next layer of powder continues. A three-dimensional object is formed through successive fusion of cross-sectional area through selectively melting of powders on the powder bed in a layer-by-layer fashion. The consecutive process of melting and dispersing of powder on the work table continues until the three-dimensional part is finished.
It is important to control the energy beam directed to the work bench, while maintaining a proper powder distribution. The fusion of powder according to the three-dimensional object can lead to powder smoke, as a result of charging of powder that may repel each other, and floats from the powder bed. A preheating of the work table needs to be performed prior to spreading of the powder. The fusion of powder in room temperature on the work piece using the energy beam may lead to the smoking incident in the work bench. The smoking incident of the powder may cause failure of the fabrication process.